Embossing rollers and method of embossing

ABSTRACT

A new and useful method for modifying embossing rollers, plates or dies is provided capable of imparting any relief pattern or texture of the highest quality to textiles, paper, synthetic materials including artificial leather, plastic materials including vinyl and polyamide fabrics, sintered metals, wood, sheet metal, and the like. In one specific embodiment of the invention, a method is provided for modifying embossing rollers capable of imparting to the surface of a vinyl plastic material, the appearance and texture of smooth kid leather.

ited States Patent Coll-Palagos [4 1 Mar. 4, 1975 1 1 EMBOSSING ROLLERS AND METHOD OF EMBOSSING [75] Inventor: Miguel Coll-Palagos, Rye, NY.

[73] Assignee: Stauffer Chemical Company,

Westport, Conn.

[22] Filed: Aug. 4, 1972 [21] Appl. No.: 277,959

Related U.S. Application Data [631 Continuation of Ser. No. 858,136, Sept. 15, 1969,

abandoned.

[52] U.S. Cl 264/219, 204/25, 204/34, 204/41, 264/293 [51] Int. Cl. B29c 1/02, B28b 11/08, C23b 5/56 [58] Field of Search 204/23, 25, 41, 32 R, 34; 101/28, 32; 264/293, 288, 219; 156/219 [56] References Cited UNITED STATES PATENTS 2.217.015 10/1940 Gurwick et a1. 204/25 3,022.231 2/1962 Broderick 204/25 3,141,051 7/1964 Takai 264/293 3.280.736 10/1966 Schafler et al 204/41 3.310.860 3/1967 Gronholz 204/34 3.31 1,692 3/1967 Baird 264/293 3,478,684 11/1969 Schafler et al 204/41 3.697349 10/1972 Andraschek et a1 264/293 FOREIGN PATENTS OR APPLICATIONS 503,132 5/1954 Canada 632,377 12/1961 Canada ..204/25 OTHER PUBLICATIONS Polishing of Steel by Electrolytic Methods, by C. B. F. Young & W. Brytczuk, Metal Finishing, May 1942, pgs. 237, 238, 240, 241.

Crodon in Paper Mills, Jan. 10, 1933.

Chromium Plating in the Paper Industry, Crodon, Jan. 10, 1933.

Primary E.tan1inerT. M. Tufariello [57] ABSTRACT 7 Claims, No Drawings This is a continuation of application Ser. No. 858,l36,filed Sept. 15, 1969, and now abandoned.

The process includes the steps of electropolishing the surface of the engraved roller, plate or die, electroplating a deposit of a metal having a high to medium levelling effect and brightness over the entire surface of the roller and plating the roller with a metal characterized by a relatively lower levelling effect, as a finishing coatmg.

FIELD OF THE INVENTION The present invention relates to a new and improved embossed roller, plate or die which is obtained by electropolishing the surface of an engraved roll'er in order to enhance the sharpness of the features of the engraving, electroplating a deposit of a suitable metal having a high or medium levelling effect, such as copper, over the entire surface of the roller and a second plating with a metal having a lesser levelling effect such as chromium, as a finishing coating. The new and improved roller thus obtained is capable of reproducing fine and delicate designs from an original pattern thereby providing high fidelity in the reproduction operation.

DESCRIPTION OF THE PRIOR ART For many years, the embossing industry has searched for new methods and procedures to create and reproduce faithfully, embossing and graining rollers, plates or dies so as to impart, on suitable substrates such as paper, leather, artificial leather, synthetic materials such as thermoplastic materials, synthetic fibers, vinyl fabrics, metal foil, and the like, relief patterns or textures of the highest quality and appearance. Unfortunately, these attempts have met with limited success since the copy or result is not generally as detailed or as fine a high fidelity reproduction as desired. Thus, details of objects of nature such as leaves, flowers, etc. become obscure or obliterated, or, in other instances, in reproducing smooth-surface articles such as kidskin or patent leather, the copy is not as smooth or the texture is not of the quality comparable to the original material. In many instances, additional steps are required such as, for example, buffing or other finishing steps but even such added efforts do not create a reproduction comparable to or simulating the texture, appearance, or quality of the original material. When relatively minute details are involved, reproductions are most unsatisfactory.

Conventional procedures whereby the industry attempted to impart embossing effects on different materials included, for example, machine engraving and electroforming. Machine engraved embossing rollers do not however possess the surface finish quality which is required, for instance, to impart the brilliance and richness of fine leather grains on vinyl fabric material. Electroforming, on the other hand, has not yet developed the mold-making technique that would assure a successful and accurate reproduction of a seamless embossing roller or cylinder which is required to emboss faithfully the delicate patterns and textures that are required and demanded for example, in footwear, wearing apparel fine upholstery fabrics, and the like.

Thus, conventional embossed rollers could not successfully reproduce articles of clothing such as, for example, leather products i.e., kidskin, fine figures or surface details. The reproductions of kidskin usually obtained were characterized by streaks and a very hazy overall effect and such products did not possess the elegant appearance of theh original kidskin. Furthermore,

the reproductions were also marred by undesirable lines and sharp edges, and an undesirable feel. Such products did not even resemble the appearance or elegance of good quality leather. Thus, using conventional engraved embossing rollers, it was not possible to obtain a surface finish quality such as that required, for instance, to impart the brilliance and richness of fine leather grains on vinyl fabrics. Up to the present time, it was not possible to reproduce faithfully embossing and graining plates to impart on substrates such as paper, leather, artificial leather, plastics, metal foil, and the like, relief patterns or textures of a high and delicate quality.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a new and useful procedure for modifying embossing rollers, plates or dies so as to produce articles having the desired surface patterns or designs which are characterized by exceptional fidelity in every dimension. Using the modified roller of the present process there is obtained a reproduction so accurate and complete in every detail that it is difficult to distinguish the reproduction from the original design. The reproduction is so faithful that even weavers imperfections are duplicated with exact fidelity when the master original involves a cloth or like material. The embossing roller obtained by the process of the present invention can thus reproduce articles so faithfully that there is scarcely any limitation with respect to the type of design or pattern which the master original may have. Any conventional design or any new design or pattern found in nature or made by man, in whatever fashion, can be reproduced not only in appearance but also in feel and textural reflexion. The modified embossed roller obtained by the process of this invention may also reproduce, in a 2- or 3- dimensional configuration, any design or pattern such as that found on the surface of drapery material, upholstery, tablecloth fabric, leather, reptile or animal skin, wood, tapestry, carpeting, crinkle foil, linoleum and the like.

In accordance with the process of the present invention, there is obtained a new and improved embossed roller by subjecting a machine engraved or electroformed roller to a combination of steps involving l an electropolishing step followed by (2) a bright metal plating step with a metal characterized by a high or medium levelling effect, to produce a combined brightening and smoothing effect on the roller. Illustrative metals are copper, iron, nickel, and the like. There is thus obtained a deposit of a metal having the aforesaid smoothing and brigtening effect over the entire surface of the embossing roller. This is followed by (3) a second plating step which is used as a finishing coating for the roller and the second plating is suitably effected by the use of a metal having relatively lower levelling effect such as chromium or nickel. The second plating step provides a hard coating surface which is resistant to corrosion and erosion while at the same time enhancing the textured pattern of the end desired product.

The order of aforesaid steps is not critical as the electroplating with a metal having a low levelling effect can precede the electroplating step wherein a metal having a high levelling effect is used. These steps can then be followed by the electropolishing step.

The shape and configuration of the embossing rollers, plates or dies employed in conjunction with the new method of the present invention is not critical and it is to be understood that any roller, plate or die of practically any shape suitable for imparting the desired grain or texture to the material which is to be embossed is acceptable for use in conjunction with the present process. The roller, plate or die can be made of a wide variety of materials including ferrous or non-ferrous metals such as aluminum and aluminum alloys. The advantages of aluminum rollers are that such rollers are characterized by better heat transfer, easier machining and less weight then steel rollers. Further, it is also possible to utilize effectively plastic rollers having a metal coating on the surface and illustrative plastic rollers are those fabricated from polyvinyl chloride, rigid urethanes, and the like.

The procedures used in engraving embossing rollers, dies, plates and the like, are conventional and the particular method employed for engraving is not critical to the success or operability of the present process. Thus, the embossing rollers, plates or dies, can be engraved by many procedures and illustratively, by hand, by machine, chemical or photochemical techniques.

Using the present procedure, quite surpisingly, it is now possible to obtain a modified roller, plate or die which can successfully impart a natural grain to paper, aluminum foil, synthetic materials such as polypropylenes, urethanes, cellulose, synthetic fabrics, and the like, and even to a material such as wood. Surprisingly, the modified rollers obtained by the present process can be applied to any material that can be embossed whether such material is a synthetic or a natural substance. Thus, for example, modified rollers of the present process, when applied, for example, to the reproduction of kidskin, the resulting product is characterized by a glossy and shiny brilliance, an excellent feel or touch; the product looks like a skin which has actually been blended in.

Where an electropolishing step was used, in prior procedures, in an attempt to improve the appearance of products obtained by conventional embossing rollers, there was some improvement in the appearance of the product but still, where an'attempt was made, for example, to simulate the appearance of natural leather, the resulting electropolished product still did not possess the desired gloss, shiny brilliance or touch of natural leather. Further more, such electropolished products also did not possess the desired fine figures or details characterizing the natural kidskin.

The present invention accordingly represents an important improvement in the art since it avoids the disadvantages associated with the use of conventional embossed rollers. The new and improved process of the present invention involves a combination of steps including l electropolishing the embossed roller, modifying the roller with (2) a bright metal plating and (3) a second metal plating step. In the first plating step, the metal used in generally ductile and bright having a high or medium levelling effect on the surface of the roller. Suitable metals include for example, copper, nickel or iron. It has been found that the use of copper is most suitable. In the second plating step, generally a metal having a relatively lower levelling effect such as, for example, chromium or nickel, is used.

The electropolishing step is a conventional one involving an anodic treatment over the roller thus producing both a smoothing and brightening effect. The electroplating procedures used are also conventional and involve utilizing the roller as the cathode in an electrolytic bath. The electroplating enhance the surface characteristics of the roller, plate or die so that said roller imparts to the material to be embossed, a lustrous leatherlike finish. Any suitable or conventional electrolyte can be used in the electoplating bath. As indicated above a plurality of electroplating steps is employed in order to secure the desired surface characteristics comparable to those of the original material. Thus, for example, in the production of an embossed vinyl material possessing the characteristics of a smooth kid leather which is highly desirable, for example, in the footwear industry, the first electroplating step is effected by use of a metal having a high or medium levelling effect such as copper followed by a second electroplating step using a metal having a relatively lower levelling effect such as chromium.

By use of the process of the present invention, there is obtained a modified roller, plate or die which is capable of reproducing unusual textured effects and especially those requiring fine and delicate designs, on various substrates such as, for example, vinyl fabrics. It is thus possible to obtain, for the first time, a reproduction of any textured surface characterized by great fidelity and extreme dimensional accuracy. Further, the reproduction capacity of the modified roller obtained by the present process exceeds the limits of machine engraving as there is no limitation with respect to shape, size, design or pattern.

In order that the invention may be more fully understood, the following Example is given by way of illustration only.

EXAMPLE A 6 foot embossing roller was engraved with the best smooth kid grain available. The embossing effects previously obtained on a polyvinyl chloride fabric were unsatisfactory since the fabric was characterized by a dull-plastic look and there were tool marks noted on the fabric including parallel lines. While there was some improvement in the texture of the fabric by subjecting it to electropolishing, the fabric still did not compare favorably with the natural grain or texture of kid grain.

The embossed roller composed of a conventional steel such as SAE 1035 was stripped of metals previously plated. The roller was then hung in a tank which was steel lined, said tank functioning as a cathode while the roller functioned as the anode.

While the preferred electrolyte contained phosphoric acid and chromic acid, any electrolyte suitable for electropolishing steel, aluminum or copper can be used depending upon the cylinder metal or material.

The electropolishing of the roller is effected by subjecting said roller to the following composition under the indicated conditions:

Sulfuric acid 15% Phosphoric acid 65% Chromic acid 6% -Cont1nued Water 14% Specific Gravity 1.74 Anode Current Density 50-1000 Amp/sq. ft. Temperature 80-180F Treatment time (min) 5-20 (or as required) The micro roughness of the roller plate was reduced and some of the high points of the metal surface were removed.

After the electrolytic treatment, the roller was subjected to a copper flash from a cyanide bath having the following composition and under the following conditrons:

Copper cyanide 3.0 oz/gal Sodium cyanide 4.5 do.

Sodium carbonate 2.0 do.

Sodium hydroxide to a pH of 12 to 12.6

Cu by analysis 2.1 oz/gal Free cyanide 1.0 do. Temperature 90-100 F. Cathodic current density l0-15 Amp/sq. ft. Plating thickness 0.05-0.l thousands an inch On this copper flash, a bright acid copper was electrodeposited and the composition of the plating bath as well as the conditions are as follows:

Copper sulfate 30 oz/gal Sulfuric acid 5.5 fl. oz/gal Chloride ion 30 mg/l UBAC Make-up additive 0.75% (by wt) UBAC-Rl Additive 0.25% (by wt) Temperature Cathode current density 100 Amp/sq. ft. Agitation: Air 1-2 cfm per sq.ft. of soln. surface 1-2 mills (for our roller) Plating thickness:

Chromic acid 33.0 oz/gal Sulfuric acid 0.33 do. Bath ratio CrO /H SO 100:1 Temperature llOl F Cathode Current Density Plating thickness:

0.7-1.5 Amp/sq. ft. 0.5 mills (for our roller) The plating bath determines the levelling effect i.e., the ability to deposit inrecessed areas.

The product obtained by use of a modified roller prepared by the foregoing combined electropolishing and electroplating steps is characterized by a glossy, shiny brilliance possessing the touch" and feel of kidskin. The product is also characterized by an elegant appearance and simulates, in every detail, the appearance and texture of kidskin leather.

It is, of course, to be understood that the present invention is by no means limited to the particular methods and devices set forth above, but also comprises any modifications within the scope of the intended claims. Thus, the rollers, dies, and the like, can be made of any material having a conductive surface.

Further, the embossing rollers, molds or dies can be used on many material substrates such as synthetic materials, paper, wood, metal, and the like. Still further, as electroytes, various substances: can be suitably employed.

I claim:

l. A method which comprises embossing a substrate with an engraved embossing master surface which has been subjected to the following succession of steps:

1. electropolishing said master surface;

2. electroplating the polished master surface with a brightening metal having a high to medium levelling effect and subsequently 3. electroplating with a metal having a relatively lower levelling effect.

2. The method of claim 1 wherein the metal having a high to medium levelling effect is copper and the metal having a relatively lower levelling effect is chromium.

3. A method according to claim 1 wherein the engraved master surface is a roller, plate or die.

4. A method according to claim 1 wherein the levelling action is effected by subjecting the master surface to the electroplating action of copper, or iron.

5. A method according to claim 1 wherein the second electroplating step is effected by contact with chromium or nickel.

6. A method according to claim 1 wherein the texture, grain and effect of a smooth kid leather or a pa tent leather is reproduced on a vinyl fabric by engraving the surface ofa roller with a smooth kid grain, electropolishing the surface of said roller, subjecting the electropolished roller to a copper flash, electroplating the resulting surface with bright copper to obtain a deposit of high ductility, brightness and hardness, subjecting the surface thus obtained to electroplating with chromium and then embossing a vinyl fabric with the resulting modified roller.

7. A method according to claim 6 wherein the electropolished roller is subjected to a copper flash in an alkaline cyanide bath prior to electroplating with cop- 

1. A METHOD WHICH COMPRISES EMBOSSING A SUBSTRATE WITH AN ENGRAVED EMBOSING MASTER SURFACE WHICH HAS BEEN SUBJECTED TO THE FOLLOWING SUCCESSION OF STEPS:
 1. ELECTROPOLISHING SAID MASTER SURFACE,
 2. ELECTROPLATING THE POLISHED MASTER SURFCE WITH A BRIGHTENING METAL HAVING A HIGH TO MEDIUM LEVELLING EFFECT AND SUBSEQUENTLY
 2. The method of claim 1 wherein the metal having a high to medium levelling effect is copper and the metal having a relatively lower levelling effect is chromium.
 2. electroplating the polished master surface with a brightening metal having a high to medium levelling effect and subsequently
 3. electroplating with a metal having a relatively lower levelling effect.
 3. A method according to claim 1 wherein the engraved master surface is a roller, plate or die.
 3. ELECTROPLATING WITH A METAL HAVING A RELATIVELY LOWER LEVELLING EFFECT.
 4. A method according to claim 1 wherein the levelling action is effected by subjecting the master surface to the electroplating action of copper, or iron.
 5. A method according to claim 1 wherein the second electroplating step is effected by contact with chromium or nickel.
 6. A method according to claim 1 wherein the texture, grain and effect of a smooth kid leather or a patent leather is reproduced on a vinyl fabric by engraving the surface of a roller with a smooth kid grain, electropolishing the surface of said roller, subjecting the electropolished roller to a copper flash, electroplating the resulting surface with bright copper to obtain a deposit of high ductility, brightness and hardness, subjecting the surface thus obtained to electroplating with chromium and then embossing a vinyl fabric with the resulting modified roller.
 7. A method according to claim 6 wherein the electrOpolished roller is subjected to a copper flash in an alkaline cyanide bath prior to electroplating with copper. 